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Discussion Starter #1
I currently have an 89 SWB with 4.0 and I have a 92 LWB with the 4.2
Nearly the same amount of miles (approx 200,000)
The 4.2 drives 10 times better. So much more power.
I have some steep hills in my area. The 89 almost does not make it up where the 4.2, I need to take my foot off the gas sometimes to slow down around corners.

The 89 passed California smog with flying colors.
I do have slightly bigger tires but I can't imagine that is the problem.


What could be the problem?
Where should I look next?

Thanks all
 

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Discussion Starter #2
Tell me if you think I am on the right track.
I cant get up a hill easily, because I think it is shifting into 2nd too early.

I went out testing today and found the 4.2 shifts into all gears at around 3000 RPMs when I put my foot into it.
When I do that on the 4.0, from 1st to 2nd, it shifts at 2000 RPMs and it takes a while to catch up and then shifts OK in other gears

I think when I go up hills (they are usually starting in 1st) The 4.0 shifts into 2nd too early and then I never really get a good start at it

Could it be kickdown cable? Shift cable? Bad transmission?

What do you all think?
 

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IMHO, shifting 1-2 at 2000 RPM with your foot in it is way too early. Think you might be on to something. As far as kickdown, I don't know anything about older RRs (mine's a DII), but you should follow that line and see if it gets you where you want to be. Could be a simple fix.
 

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Shifting the transmission by hand up hill is what I think you should do
The kick down cable is More for jumping into traffic and passing
Also replacing that cable isn’t exactly an easy fix
Look at its connection to the throttle body
And see if it needs adjusting
 

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Discussion Starter #5
So here are a couple things I have found/learned.
I feel like a bit of an idiot, but when I was checking the kickdown cable and throttle cable, I saw that the hose clamp that I have on the hose directly in front of the throttle was facing stright up. In other words, when the car was given full throttle, it was stopped by the head of the clamp. I just needed to loosen it and turn it and then I have 15% more throttle.
Something else that I learned is that going to a 265/75/16 tire can lose anywhere from 13% of power without changing gear ratios. I am not sure how that was calculated.
My 92 have stock wheels and tires. I may swap them just to see the difference there.
With those 2 factors, I believe I have my answer.
Going up long steep hills, I just have to manually shift it
 

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So here are a couple things I have found/learned.
I feel like a bit of an idiot, but when I was checking the kickdown cable and throttle cable, I saw that the hose clamp that I have on the hose directly in front of the throttle was facing stright up. In other words, when the car was given full throttle, it was stopped by the head of the clamp. I just needed to loosen it and turn it and then I have 15% more throttle.
Something else that I learned is that going to a 265/75/16 tire can lose anywhere from 13% of power without changing gear ratios. I am not sure how that was calculated.
My 92 have stock wheels and tires. I may swap them just to see the difference there.
With those 2 factors, I believe I have my answer.
Going up long steep hills, I just have to manually shift it
The tyres will make a hell of a difference with power and fuel economy. I have standard tyres and the same diameter tyres as yours. The difference in power is very noticeable.
On the classics the kick down cable is easily adjustable. Just adjust it to suit what you want. As I mainly use my range for towing a car trailer, I have the kick down set to change down a bit earlier than standard.
 

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Discussion Starter #8
I am hoping someone can help me with this now.

Since I have 265/75/16 tires and they rob me of quite a bit of power, what would be a good tire size for a rover 4.0 with approx 3" lift.
I have a set of 235/70/16s that I put on just to see the difference in power.
It is noticeable but not by a lot. Pretty much just when I climb hills.
I will not be keeping the 235s on there. They look ridiculous with my lift.

Here is where I need the most help.
Is the problem with the weight of the tire, the diameter of the tire, width of the tire, or.......?
I was looking at some smaller tires that I liked and they were actually heavier than what I have now. Must be the tread type.

What I have now are 31.7 diameter 10.6 width and weigh 43.9 lbs.
What I am possibly looking into are 30.5 diameter 9.8 Width and 38.6 lbs.

Will I notice a difference at all with the new setup?
Will be bummed with the stance being smaller?
Will the new setup be better overall for my rig. Meaning transmission not working as hard, less weight to have to roll, etc....

Interested in your thoughts

Thanks all
 

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Discussion Starter #10
A little update here and in need of some advice.

I just did a compression test and I think my lack of power is due to tired engine with low compression.
The test went as follows.
Just going from back to front looking toward the rover

P D
95 90
91 94
100 99
115 98

Where do I go from here?
The Rover runs perfect with no real problems other than it is very slow and I am not sure if I could hit 70MPH
 

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Discussion Starter #11
I should note that my test was done WOT and warm. Not hot but warm. Let her run for approx 10 mins
 

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Go get a vacuum gauge and test the motor with that instead. Compression tests are very inaccurate.
Is it a 3.9 or 4.0. Check the engine number.
 

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Discussion Starter #13
A very nubbie question here. Sorry. One thing I have learned about having a Rover is to have lots of tools and know how to use them
I have a vacuum tester.
Can you give me basic instructions on where I should connect it so I can get you some accurate results?
 

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Discussion Starter #14
Heres my test results.
Let me know if I installed the vacuum tester in a good place.
That picture is with the engine running. The needle stayed right where it is. When I blip the throttle, it jumps to 0 and then right back to what you see in pic.
91463
 

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Discussion Starter #15
Some extra info
I am at approx 6200ft elevation
At 2500RPMs it holds steady around 14
When at idle, it runs 12-13
 

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A very nubbie question here. Sorry. One thing I have learned about having a Rover is to have lots of tools and know how to use them
I have a vacuum tester.
Can you give me basic instructions on where I should connect it so I can get you some accurate results?
You can google the various Vacuum gauge movements and what they mean. By your picture you have good vacuum at idle. But it is more about whether the reading is fluctuating, etc, which I can't see from a still photo.
91464
 

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Discussion Starter #17
I can tell you this.
When cold it just sits at 12
I just took it for a drive and warmed it up. Sits between 12 and 14. Not fast moving. Pretty steady
Gauge says 17-22 =normal motor
Mine reads average 13. Almost to red ignition timing area on the gauge.

This motor is a bit old at approx 250,000 miles
 

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I can tell you this.
When cold it just sits at 12
I just took it for a drive and warmed it up. Sits between 12 and 14. Not fast moving. Pretty steady
Gauge says 17-22 =normal motor
Mine reads average 13. Almost to red ignition timing area on the gauge.

This motor is a bit old at approx 250,000 miles
I was looking at the numbers on the outside of your gauge, which was wrong. Yes, you have low vacuum and combined with you compression test, and that you state that it has 250,000 miles, it has probably seen better days.
 

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Discussion Starter #19
I am prob buying a 3.9 with approx 120,000 miles. Ran "great and strong" when pulled. Think the vehicle was totalled
 
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